Definitive support by transmission electron microscopy, electron diffraction, and electron density maps for the formation of a BCC lattice from poly[N-[3,4,5-tris(n-dodecan-l-yloxy)benzoyl]ethyleneimine)

Transmission electron microscopy (TEM), electron diffraction (ED), and elec tron density maps (EDM) experiments were carried out on a poly{N-[3,4,5-tri s(n-dodecan-1-yloxy)benzoyl]-ethyleneimine} {poly[(3,4,5)12G1-Oxz]} with a degree of polymerization (DP) of 20. All experiments confirmed the thermotr opic body-centered cubic (BCC) Im (3) over barm lattice suggested previousl y by X-ray diffraction (XRD) experiments. The unit cell parameter determine d by ED at 23 degreesC is a = 42.4 Angstrom, in good agreement with XRD res ults which show a = 42.6 Angstrom after quenching from 70 degreesC. EDM of the XRD results confirm that the supramolecular minidendrimer obtained from poly[(3,4,5)12G1-Oxz] adopts a spherical "inverse micellar-like" structure , with the polyethyleneimine backbone and the aromatic groups microsegregat ed and concentrated in the corners and in the center of the cubic unit cell . A space-filling continuum is realized by the n-alkyl groups that radiate out of the aromatic core of the spherical dendrimer. This manuscript is onl y the second example of complete structural analysis of a lattice generated from supramolecular objects and complements the previous example reported from our laboratory on the Pm (3) over barn lattice.